Drill pipe protector



B. s. MINOR 3,449,022

DRILL PIPE PROTECTOR June 10, 1969 v Filed May 27, 1968 Sheet of 2 INVEUR. B027 STAAJLEY "v06 8 Y kg; 6441 I prmefvs B. S. MINOR June I 10,1969 DRILL PIPE PROTECTOR Sheet Filed May 27, 1968 I N VLi'N'l ()R. BUQTSTA/JLEV Mme? United States Patent 3,449,022 DRILL PIPE PROTECTOR BurtStanley Minor, 1811 E. Kanola, La Habra, Calif. 90631Continuation-impart of application Ser. No. 573,706,

Aug. 19, 1966. This application May 27, 1968, Ser.

Int. Cl. F16c, 1/26, 17/00, 21/00 US. Cl. 3084 6 Claims ABSTRACT OF THEDISCLOSURE This application is a continuation-in-part of my copendingapplication Ser. No. 573,706, filed Aug. 19, 1966, and relates toimprovements on the invention described in application Ser. No. 490,878,filed Sept. 28, 1965, both of which are now abandoned.

In drilling deep bore holes such as in oil well drilling, the drillholes are usually of such depth that the metal drill stem or pipe whichcarries the drill tends, during rotation in the hole, to whip laterallyinto abrasive engagement with the metallic well casing lining the hole;and consequently it is customary to prevent such abrasive metal-to-metalengagement between the drill stem and well casing by means ofconstricting a pipe protecting device about the drill stem.

In broad essence, such protectors conventionally comprise an annularelastomeric sleeve-like body having a metalic reinforcing band embeddedtherein. The outer layer or portion of the elastomeric body on theoutside of the reinforcing band is usually substantially thicker thanthe inner layer and therefore possesses relatively more elasticity. Whenapplied to a drill stem, the inner layer must have such frictionalengagement with the drill stem as will prevent the protector fromslipping on the drill stem. conventionally, this friction is obtained bytensioningthe protector about the drill stem, which radially compressesthe inner layer between the drill stern and the reinforcing band of theprotector. In most protectors, the annular body and its embeddedreinforcing sleeve are longitudinally split, the protector beingconstricted about the drill pipe by a latch mechanism which draws theends of the protector together at the split.

A major problem inherent in the use of conventional protectors is thedifficulty of obtaining such frictional engagement of the inner layeragainst the drill stem as will effectively prevent such relativeslippage, without compressing the inner layer beyond its maximum modulusof elasticity. When there is such excessive compression of the innerlayer, the elastomeric material of that layer rapidly deteriorates bylosing its elasticity, resiliency and recovery capabilities, and mypresent invention has for its main object the overcoming of thatproblem.

More particularly, it is my object to provide a protector so constructedthat when the inner layer of the elastomeric body is under compression,the compression may be kept below the maximum modulus of elasticity ofthe material 'by extruding some of the material outwardly throughcritically shaped and located, resiliently interrupted slots in thereinforcing band; and the opposition ice to this extrusion provided bythe resilient slot interruptions and the resilience of the outer layerassures the necessary frictional engagement of the inner layer with thedrill stern.

It is a further and more particular object to concentrate thecompressive forces by applying them directly against the resilient slotinterruptions.

It is a still further and more particular object to so proportion thesaid boss portions and slots that they will have substantially the samelength and width dimensions.

Still further and subordinate objects and advantages will becomeapparent to those skilled in the art from the following detaileddescription of a presently prefer-red embodiment of my invention whereinI shall refer to the accompanying drawings in which:

FIG. 1 is a side elevation of my protector constricted about aconventional metallic drill stem;

FIG. 2 is an enlarged cross-section taken on line 22 of FIG. 1;

FIG. 3 is similar to FIG. 2, 'but shows the device detached from thedrill stem;

FIG. 4 is a section on line 4-4 of FIG. 3;

FIG. 5 is a section on line 55 of FIG. 2;

FIG. 6 is an enlarged fragmentary section on line 6-6 of FIG. 4;

FIG. 7 is an enlarged fragmentary section on line 77 of FIG. 5;

FIG. 8 is a free face view of the reinforcing band; and

FIG. 9 is an enlarged fragmentary elevational view of the inside surfaceof my protector.

In the drawings, 5 denotes a conventional metallic drill stern aboutwhich is constricted, by a latching mechanism 10, my improved splitprotector body 7.

The protector comprises an annular body of elastomeric material having arelatively thick outer layer 15 and a. relatively thinner inner layer16, reinforced by metallic band 20 sandwiched between and bonded tothose layers.

The body and band are longitudinally spit at 21, the extremity portionsof the band along the split being backwardly bent upon the reinforcingstrips 22. Secured to said extremity portions, as by riveting (notshown), the extension or keyway-forming members 23 provide, at andadjacent the split, interengaging, circumferentially opposed, tongue andrecess portions 24, 25, extending across the split. The extensionmembers 22 are of U-shaped cross-section so that when the tongue andrecess portions are interengaged, they define a keyway 31 extendinglongitudinally along the split for the reception of a metallic latchingkey 32. The elastomeric body has side extremity portions 33 at the splitin which the extension members 23 of the band are embedded.

The inner layer 16 of the elastomeric material is so formed or molded asto define spaced drill stem-engaging boss portions 35 and interveningweb-like portions 36. The boss portions are each generally chordal inshape, being of maximum thickness between their ends and becominggradually thinner toward their ends.

The reinforcing band 20 is provided with spaced elongated slots 37directly outwardly of and in registering communication with respectiveboss portions 35; each of said slots being interrupted by a pair ofcircumferentially opposed resilient fingers 40, 41, the outer ends ofwhich fingers are preferably formed integral with the band, that beingthe only point at which the respective fingers are attached to the bandand the point about which the fingers resiliently flex as will behereinafter described. The outer or free ends 43 of the fingers arepreferably rounded at 44 and terminate in circumferentially spacedrelationship to provide a small space 45 therebetween. The width of therespective bosses is substantially the same as the Width of the bossesalthough preferably the width of the bosses is of the order of ,4 lessthan that of the slots. The

chord length of the respective bosses 35 is preferably the same or atleast no greater than the length of the respective slots.

When my protector is tensioned about a drill stem, that compression ofthe inner body layer 16 comprising the bosses 35 is compressed betweenthe drill stem and the resilient fingers 40, 41 while the relativelythin or weblike portions 36 of the inner layer are compressed betweenthe drill stem and the portions of the band between the slots 37. Thecompression of the bosses extrudes elastomeric material of the bossesagainst the inner surfaces of the resilient fingers 40, 41, flexingthose figures outwardly as best shown in FIG. 7. Some of the extrudedmaterial passes into the outer layer 15 through the spaces 45 betweenthe respective pairs of fingers, becoming dispersed in andcommensurately increasing the resiliency of the outer layer.

While this outward extrusion sufficiently relieves the compression ofthe bosses to avoid their elastomeric material being excessivelycompressed, the resultant lessening of the frictional engagement of theinner surface of the protector with the drill stem is compensated for bythe opposite or inward pressure exerted on the outer surfaces of theresilient fingers, so that the desired frictional engagement ismaintained.

The bosses 35 and the slots 37, being in direct register andcommunication with each other, the extrusion is greatly enhanced andfacilitated since the compressive forces are concentrated on the slotsand the resilient fingers.

The chordal shape of the bosses causes the greatest outward extrusiveforce to be applied to the fingers at and adjacent their free outerends, where they oifer the least opposition to the extrusion.

To install my protector on the drill stern, it is manually spread apartsufficiently to enable the protector to be applied laterally about thedrill stem. After the extremity portions of the band are interengaged atthe split 22, which is accomplished by a conventional clamping tool, notshown, whose jaws are inserted in the holes 50, opening through theperiphery of the body, the latching key 32 is inserted through theregistering holes or loops 30 in the interengaging portions of the band,to latch the protector in tension about the drill pipe.

I claim:

1. A protector device for preventing abrasive contact between a metallicdrill stem and a drill hole metallic casing, comprising an annular,longitudinally split body of elastomeric material having concentricinner and outer elastomerie layers, and a longitudinally split metallicreinforcing band mounted between and bonded to said layers; the innerlayer of said body presenting spaced drill stem-engaging, radiallycompressible and extrudable boss portions thickest medially betweentheir ends and of gradually decreasing thickness toward their ends; andmeans for constricting said band about said drill stem whereby radiallyto compress said respective boss portions and to extrude the materialthereof; and means associated with said band for relieving said radialcompression of said boss portions and for maintaining frictionalengagement of said boss portions with said drill stern; said lattermeans comprising spaced, extrusion-passing, elongated slots through saidband directly opposite and in register with said respective bossportions; said respective slots being yieldably interrupted bycircumferentially opposed pairs of resilient fingers secured to the bandonly at the ends of said respective slots, whereby to be flexedoutwardly at and adjacent their inner ends in response to the extrusionresulting from the radial compression of said respective bosses, andwhereby to be flexed inwardly in response to the combined resiliency ofsaid fingers and the elasticity of said outer layer.

2. The device of claim 1 wherein said fingers are unattached to saidband except at their inner ends.

3. The device of claim 1 wherein each of said fingers has curved outerend edges.

4. The device of claim 1 wherein said fingers, when unflexed, aresubstantially in the plane of the contiguous portions of said band.

5. The device of claim 1 wherein the respective inner end portions ofsaid fingers are integral, with said band.

6. The device of claim 1 wherein said respective boss portions aresubstantially of the same width and circumferential length as saidrespective slots.

References Cited UNITED STATES PATENTS 1,965,998 7/ 1934 Williams.2,002,893 5/1935 Holt. 2,251,428 8/ 1941 Smith. 2,380,715 7/1945 Aker308238 2,897,016 7/1959 Baker. 3,051,532 8/1962 Collett. 3,054,646 9/1962 Minor. 3,094,360 6/ 1963 Collett. 3,147,963 9/ 1964 Frazier.

MARTIN P. SCHWADRON, Primary Examiner.

LUCIOUS L. JOHNSON, Assistant Examiner.

U.S. Cl. X.R. 2871 11

